No. Both have their own importance and place in the testing of renal function, morphology and urodynamics

In pediatric age intravenous pyelography has a very limited use. The same information can be obtained by ultrasound (as a matter of presence of calculi, dilation of upper urinary tract, etc)

The two examinations have distinct purposes. If your objective is the detection of the calculi you should choose an anatomic exam because scintigraphy will not detect the calculi but only the obstruction to urinary excretion. But if you are already aware of the calculi and you are investigating the functional damage of the calculi and intend to follow through time renal function, renal scintigraphy should be your choice. So each study has its own purposes, advantages and disadvantages, being a complement of each other.

I would not do any of both modalities. I would just go for non contrast CT urinary system. This would anatomically define the stone and shows the renal parenchymal thickness of the obstructed kidney. I would not choose IVU and diuretic renogram would be highly falacious, as the obstruction would be associated with a higher bowman's capsule pressue that negatively affect the filtering pressure even with a remaining adequate renal parenchyma.

A clinical exam of the patient, plain film of the abdomen and an in-office renal/ureteral USG by the physician can detect the level of obstruction and give an idea of the degree of hydronephrosis which impacts renal function. These findings are an indicator of what clinical treatments are needed to restore renal function to normal which should be the goal of management rather than one simple measure of function.

There are 2 possible questions best answered by a scintigraphic renograph (not renal scintigraphy): 1: is there an obstruction? 2: Is renal function decreasing on the obstructed side.

I guess spiral CT is the modality of choice in that situation unless there is a big concern regarding renal function. Despite it gives good idea about renal parenchymal thickness, it doesn't replace the 

Not sure.

Yes, particulary in peditrica patients and in ptients senstive on iodine contrasts.

Non contrast hélicoïdal CT should be thé modality of choice. Practically Indications for IVP are replaced by à Ct followed by injection of contrast. Rénal scintigraphy is to évaluate obstruction rénal fonction or rénal scar

 Scinctigraphy is a functional study while IVU is an anatomical as well as  functional study. So renal scan can never replace an IVU or CT urography.

  In paediatric patient where usg provides good anatomical details and stone is find out , one can directly go for renal scan to avoid radiation.

In case of an obstructing calculus, the question is where is the level of obstruction. A preliminary Sonography would say whether Hydronephrosis or Hydrouretronephrosis present, and then the likely site of calculus. Next in order would be CT to determine the modality of intervention. At last would be the scintigraphy, especially in cases of staghorn calculus to see how poor the renal function is, which would assist in decision making.

Fair enough, but, but a dilated collecting system is not the same as an obstruction.

Dear Goris, agreed. Dilatation of pelvi calyceal system refers to Hydronephrosis. Dilatation often points to the site of the problem.

Unilateral hydrouretero nephrosis without any stone visualised may indicate a recently passed calculus.

Thanks

Hello S.V. Krishna Reddy

Apologies for not entering the discussion sooner! It is interesting that my view has changed over time…

I think Vinod Priyadarshi and George Coura-Filho said it very well when they distinguished anatomical and functional Imaging. That is what makes radiology and nuclear medicine so different! That is true for all tests in nuclear medicine…

So the answer to your question must be no…